Environmental instrumentation today provides for measurement of a variety of different parameters. The parameters that are measured may include volatile organic compounds, toxic gas, air velocity, carbon dioxide, particulates, percent relative humidity, differential pressure, ozone, ammonia and other parameters. Sensing these parameters is generally accomplished using probe assemblies having one or more sensors.
A typical probe assembly may include a PIC microcontroller based printed circuit board with multiple sensors mounted in sockets. Different sensors may have different analog or digital outputs, may require different scaling parameters and signal conditioning techniques, and are typically installed at the factory. Furthermore, the sensors may be configured via a combination of links soldered to or removed from the printed circuit board. The PIC microcontroller of the probe assembly may then be programmed for the installed sensors using a processor running a proprietary software program. As a result, probe assemblies have a rigid fixed configuration where sensors may only be changed out by factory personnel and the reconfigured probe may only be programmed while connected to a factory base unit running the proprietary software program. Factory reprogramming may also be required in order to change scaling parameters and for updating signal conditioning techniques.
Different sensors may have different characteristics that may change as the sensor operates and cause inaccurate readings. In addition, different sensing techniques may require different air flow velocities resulting in a return to the factory for additional reconfiguration.
It would be advantageous to provide an end user with the ability to install different sensors in a probe and have the probe automatically reconfigure itself to accommodate different sensors, sensor parameters, and signal conditioning techniques.